A drum is a percussion musical instrument that can include a cylindrical drum body or shell defining a typically hollow chamber and a drum skin on one or both ends of the shell. Each drum skin can be mounted in a counter hoop to support the skin. A lug can be provided to couple the hoop to the shell of the drum using a tension rod to aid in tensioning the drum skin.
Various types of lugs have been used such as tube lugs and hollow cast lugs in the tensioning devices. A tube lug includes a casing having a tube shape where an end of the casing is threaded to receive the tension rod. However, if the tube of the casing is not perfectly aligned with the tension rod, the tension rod may thread onto the tube at odd angles and cause misalignment. Misaligned tension rods can create undesirable stress on the shell and undesirably affect the resonance and pitch of the drum.
A hollow cast lug can be used to provide better alignment with the tension rod to reduce stress applied to the shell and improve resonance within the shell. The hollow cast lug can include an insert to receive the tension rod, and a spring or elastic material such as rubber to hold the insert in place. However, the spring or elastic material may undesirably affect acoustic characteristics of the drum.